Examples of breakthrough koans would be: "Mu",
"Who am I?', "What is mind?", and "What is the sound
of one hand?"
The role of the breakthrough koan is to smack or
break through the dualistic, conceptual thought consciousness based on a
false sense of an ego-I self. Thus, one's mind is opened to the
beginning-less, endless fundamental truth of the universe. In essence,
there is an awakening to one's sovereign nature.
With intense effort the breakthrough koan takes
one's natural questioning beyond thought and perception, beyond the
relative and the absolute, to awaken to that which has always been there
but has been obscured by clouds of delusion. This breaking through is
like recalling something always known yet somehow forgotten. It's
comparable to turning a light on in a dark room. The room has always
been the same. It's only that people have been groping in darkness,
unable to really live in that room.
In the breakthrough koan practice, students must
demonstrate the truth of the koan and can't merely present theories or
ideas.

A koan (in
Korean kong-an) is a puzzling proposition or phrase. This phrase
is not merely a paradox designed to shock the mind into instant
Enlightenment. It is an integral part of a system honed over centuries
to help bring a student to a direct realization of ultimate reality.
From the Japanese ko meaning public, and an meaning
proposition, koans can be questions, excerpts from sutras,
episodes in the life of a master, or just a word from a famous dialogue
(Jap.: mondo) or teaching.
There are about 1,700
traditional koans in existence. An appropriate koan can have the
effect of creating gaps in the train of thought of a
practitioner, or in reality to any one who is not really paying
attention to the conversation in the first place.
I think this is truly the
greatest task of the Teacher (Master).
That is, to understand that
the student (listener) is not really listening to, or even really
thinking about the moment.
It is even a greater task,
that is placed on the Teacher, to be able to distinguish between those
who simple like to answer questions, and those who are actually moving
along the path to Enlightenment.
One would think that someone
who is practicing Zen is really practicing Zen. And one who is answering
a Koan, is really answering a Koan.
But, this is not true.
There is this little thing
called ego. The ego wants to know that it knows. Even more to the point,
the ego wants to know that the answer is the answer. But, the answer is
only a statement of momentary fantasy.
A Teacher has an answer of
External Truth, which can not be explained or verbalized in the physical
world.
Thus the Koan. A way to
transform and transfer Knowledge of something that can not be Known. But
this "Not Known" is only referring to known as in the physical
sense. A Knowing that can not be placed on writing paper, but can be
painted on a canvas.
For the Teacher, the canvas is
"The Mind."